could unpile
Regular verb: unpile - unpiled- unpiled

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could unpile
you could unpile
he could unpile
we could unpile
you could unpile
they could unpile 	I could be unpiling
you could be unpiling
he could be unpiling
we could be unpiling
you could be unpiling
they could be unpiling	I could have unpiled
you could have unpiled
he could have unpiled
we could have unpiled
you could have unpiled
they could have unpiled	I could have been unpiling
you could have been unpiling
he could have been unpiling
we could have been unpiling
you could have been unpiling
they could have been unpiling	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could not unpile
you could not unpile
he could not unpile
we could not unpile
you could not unpile
they could not unpile 	I could not be unpiling
you could not be unpiling
he could not be unpiling
we could not be unpiling
you could not be unpiling
they could not be unpiling	I could not have unpiled
you could not have unpiled
he could not have unpiled
we could not have unpiled
you could not have unpiled
they could not have unpiled	I could not have been unpiling
you could not have been unpiling
he could not have been unpiling
we could not have been unpiling
you could not have been unpiling
they could not have been unpiling	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I unpile?
could you unpile?
could he unpile?
could we unpile?
could you unpile?
could they unpile? 	could I be unpiling?
could you be unpiling?
could he be unpiling?
could we be unpiling?
could you be unpiling?
could they be unpiling? 	could I have unpiled?
could you have unpiled?
could he have unpiled?
could we have unpiled?
could you have unpiled?
could they have unpiled? 	could I have been unpiling?
could you have been unpiling?
could he have been unpiling?
could we have been unpiling?
could you have been unpiling?
could they have been unpiling? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I not unpile?
could you not unpile?
could he not unpile?
could we not unpile?
could you not unpile?
could they not unpile? 	could I not be unpiling?
could you not be unpiling?
could he not be unpiling?
could we not be unpiling?
could you not be unpiling?
could they not be unpiling? 	could I not have unpiled?
could you not have unpiled?
could he not have unpiled?
could we not have unpiled?
could you not have unpiled?
could they not have unpiled? 	could I not have been unpiling?
could you not have been unpiling?
could he not have been unpiling?
could we not have been unpiling?
could you not have been unpiling?
could they not have been unpiling?